Apparatus for measuring the rate of drilling fluid flow through a well



y 8, 1951 J w PITCHER ETAL 2,552,454

APPARATUS FdR MEASURING THE RATE OF DRILLING FLUID FLOW THROUGH WELLS Filed May 10, 1945 2 sheets-sheet 1 cou/v I'ER STROKE cou/vn-"n STROKE J w PITCHER ETAL 2,552,454

APPARATUS FOR MEASURING THE RATE OF DRILLING FLUID FLOW THROUGH WELLS Filed May 10, 1945 2 Sheets-Sheet 2 May 8, 1951 fzmeawz LZZ/zer BY Joimf M f Wwaw Patented May 8, 1951 APPARATUS FOR MEASURING THE RATE OF DRILLING FLUID FLOW THROUGH A WVELL James W. Pitcher and John T. Callahan, Jr.,

Tulsa, Okla, assignors to Engineering Laboratcries, 1110., Tulsa, Okla, a corporation of Oklahoma Application May 10, 1945, Serial No. 59?;992

1' Claim. 1 The present invention relates to improved apparatus for measuring therate of flow of a drilling fluid through a Well during a well drilling operation and for indicating changes in the 2 apparatus characterized by the features of the present invention;

Fig. 2 is a side'inechanical View illustrating one structural embodiment of the apparatus;

rate of flow of a drilling'fluid into a well. 5 and In conventionalwell drilling operations, such, Fig. 3 is a detail'view illustrating certain coinfor example, as in the drilling of oil or gas wells ponents of the apparatus. by the rotary method, a drilling fluid or mud Referring now to thedra'wings, a'nd'more parccnsisting usually of a suspension of clay or ticularly to Fig. 1 thereof, the present improved earthy solidsin water, is forced down through a apparatus is illustrated in itsuse to measure the string of hollow drill pipe to the bottom of the rate of drilling fluid ilowtlirough a Well in well, where it is discharged for return flow upwhich is inserted a string of hollow drill pipe H wardly through the annular space between the of the character ordinarily'eniploy'edin arotary drill pipe and the wall of the Well bore to the drilling operation to rotate a drill bit !2 consurface of the ground or in reverse order. As nected to the lower end of thcdrill pipe St in pointed out in Hayward Patent "No. 2,290,179 and provided with drilling fluid openings [3. granted July 21, 1942, accurate and continuous Drilling'fluid or mud of'the type ordinarily used knowledge of the volume and rate of flow of the in a drilling operation is delivered to the drill drilling fluidthrough the well isof great imporpipe H internallythereof and under pressure by tance to the driller and is particularly important 2 means of a pump it having its discharge end in connection with'contin'uous coring or logging. connected 'to the upper end of the drill pipe It is also important in the detection of what is string I! through the usual rotary hose iii and known as wash outs in the drill pipe, which if swivel M. The pump it is of the well-known permitted to proceed without detection, result in direct acting type and is designedto operate'at a parting of the drill pipe with the resultant 'necessubstantially constant pressure which is mainsity for a fishing operation. Various methods tained against changing resistance in the stream and apparatus have been employed for obtainof drilling fluid being pumped into the drill pipe ing an indication'of the rate of drilling fluid flow string i l by a'change in the spe'ed'of the pump. for the purposes specified. In general, 'prior art The pumping piston Within the cylinder I ia is apparatus of this character is rather delicate, conventionally driven by a steam piston and and hence is not well suited to the rough hancylinder'asseinbly 20 through a piston rod 19, the dling ordinarilyencount'ered in use. The prior usual rocker arm 22 being provided to control art devices are also rather expensive to manuthe steam entrance and exit valves of't he pumpfacture and service, since the services of a skilled 'ing cylinder. This arm is pivotally supported technician are required in the calibration and adjacent its upper end and has it lower end repair thereof. connected to the usual cross head 21 which re- It is an object of the present invention, there ciprocates with the piston rod 19. Thus, during fore, to provide improved apparatus for indicatreciprocation of the pump I9, "back and forth ing the rate of drilling fluid flow through a well pivotal movement is imparted to the rocker arm during a well drilling operation. 40 22. This motion 'of the arm 22 is utilized to open It is another objector the invention to provide and close a 'set of control contacts 23, the arapparatus of the character described which is of rangement being such that these contacts are rugged and economical construction, may be closed during each pumping stroke of the pump easily installed, operated. and serviced by relaand are opened during each intake stroke of the tively unskilled users of the apparatus, and is pump. The current pulses produced through reliably accurate in its operation to provide an opening and closing of the contacts 23, are thus indication of the rate of drilling fluid flow into a generated at a rate which varies in accordance well and any changes in the rate of flow. with variations in the pumping ratejand hence The invention both as to its organization and in the rate of drilling fluid delivery to the well method of operation, together with further 010- and are utilized to control the present improved ,iects and advantages thereof will best be undermeasuring apparatus. stood by reference to the following specification In brief, this apparatu comprises an actuat taken in connection with the accompanying ing or indicating element '23 in the form of an drawings, in which: arm carried by a rotatable shaft 24 and having a Fig. 1 is a schematic view illustrating improved normal or reference setting which is determined tween the, parts 35 and 4!].

by engagement of a stop arm 25, also fixedly carried by the shaft 24, with a stop 26 fixedly mounted upon the upstanding frame member 35a of the apparatus. For the purpose of measuring the time required for the completion of certain pumping strokes of the pump 15, driving means including a constant and slow speed motor 28 are provided for moving the element 23 away from its normal setting. More specifically, the motor 28 is normally connected in driving relationship with the element 23 through a driving connection which comprises a gear train 29, 36, a shaft 3 l and a pair of engaged clutch members 32 and 33, the first of which is mounted for rotation with the shaft 3|, and the second of which is mounted for rotation with the shaft 24. The shaft 24 is journalled for rotary and axial movement in a bearing member 38 which is carried by the frame member 34a. This bearing member is provided with an enlarged cup-shaped part 38a which houses a helical restoring spring 39 having the function of normally biasing the shaft 24 and the el ment 23 to their respective normal settings, i. e., to positions wherein the stop arm 25 engages the stop 26. The motor 28, gear train 255, 39, shaft 3| and clutch member 32 are supported upon a second upstanding frame member 341), suitable bearing means being provided upon this frame member for receiving the shaft 3|. For the purpose of normally maintaining the two clutch members 32 and 33 in clutching engagement, a compression spring 3'! is provided which is held under compression between the end of the bearing member 38 and the clutch member 33. To provide for intermittent declutching of the two clutch members, a clutch release mechanism is provided which comprises an element 35 mounted by the shaft 24 and movable axially and rotatably relative thereto. This element is interposed between the clutch member 33 and a thrust member 36a keyed to the shaft 24 and against which the spring 31 directly bears. A ball bearing assembly 35 is interposed between the element 35 and the thrust sleeve 35a, and a second ball bearing assembly 34 is provided between the clutch member 32 and the bearing for the shaft 3!, these two bearing assemblies coacting to absorb the thrust of the spring 3'! when the two clutch members are engaged, and thus provide for unrestricted rotation of the two shafts 2t and 3| under the influence of the motor 28. Similarly, a ball bearing assembly 3% is interposed between the thrust member 36a and the left end of the spring 31 to coact with the ball bearing assembly 36 in permitting free rotation of the shaft 24 under the influence of the retracting spring 39 when the two clutch members are disengaged.

Declutching of the two clutch members 1-32 and 33 is effected through operation of an electromagnet ts having a plunger 42 which is adapted to thrust against the lower end of an arm in pivotally mounted by means of a pivot pin ll upon a supporting member 21 which is carried by and projects laterally from the upstanding frame member 34a of the device. At its opposite end, this arm is bifurcated to embrace the element 35, and the bifurcations carry opposed fingers entering the channel of this element to provide the required mechanical connection be- As explained below, the solenoid 43 is arranged for intermittent energization under the control of the contacts 23. at the rate of one energizing pulse for each alternate stroke of the pump l6.

'through a master switch 63.

For the purpose of indicating the off-normal settings which are imparted to the element 23 through operation of the above-described facilities, indicating means are provided which comprise a rotatable shaft 44 having mounted for rotation therewith an indicating pointer 50 which is cooperable with a scale 5| to identify the angular setting thereof. If electrical means are to be employed in indicating the rate of drilling fluid flow as represented by the angular setting of the shaft 46, this shaft may also be utilized to control the setting of an adjustable potentiometer 47 mounted upon the frame member 3 30 and having a wiper arm 41a rotatable with the shaft 44 in sliding engagement with a resistor element 411). This potentiometer may be used to control the indication of a' measuring instrument 49 having its scale appropriately graduated in terms of drilling fluid flow. A one-way lost-motion driving connection is provided between theshaft M and the element 23 for the purpose of causing this shaft to follow movement of the element 23 away from its normal setting. This connection comprises a reel or drum 45 fixedly connected to the shaft 44 adjacent the element 23 and provided with an eccentrically mounted pin 46 which is engageable with the element 23.

In order to rotate the shaft 44 in the reverse direction when the increments of movement of the element 23 away from its normal setting are decreased, reverse driving means are provided which comprise a torque motor 52 supported by the frame member 34c. This motor is arranged for intermittent energization under the control of the pump 16 and is provided with a pulley 53 fixedly connected to its rotor shaft and connected by means of a string 54 to the pulley 45. One or two turns of this string are wrapped around each pulley and the respective ends thereof are fixedly attached to the two pulleys.

In order to energize the motor 52 and the magnet 43 during alternate strokes of the pump [6,

and in accordance with variations in the rate of operation of this pump, a control device 9 of the magnet operated, ratchet and pawl type is provided. Specifically, this device comprises a contact spring assembly 56; the inner spring 56a of which is arranged for actuation by an eight point star wheel 5'! mounted for rotation with a shaft 53 which also carries a sixteen tooth ratchet wheel 59. This ratchet wheel is arranged for actuation by a spring biased pawl 62 carried by a spring biased armature 6| in response to energization of the operating magnet $6. The structural arrangement of the device is such that during the delivery of alternate current pulses to the magnet 60, the contact springs making up the assembly 56 are actuated to their respective off-normal positions, and are returned to their respective normal settings during the delivery of each intervening pulse to the operating magnet 60.

For the purpose of directly counting and registering the strokes of the pump It, a pair of electro-magnetically operated counting devices 64 and 65 of any desired type are provided. Current for energizing the operating magnets of the two identified counters, the magnet 60 ofthe control device 9, the release magnet 43, the timing motor 28 and the torque motor 52, is supplied by a current source of appropriate voltage If desired, this switch may be suitably interlocked with the steam admission valve of the pump I6 so that when operation of the pump is initiated, the described apparatus for measuring the rate of drilling fluid flow will also start to operate.

In using the described apparatus in the field, the only operations required in setting up the apparatus for use are those of connecting an available current source 55 of appropriate Voltage into the circuit and appropriately connecting the conductors 55c and 55b to the contacts 23 controlled by the mud pump it. When operation of the pump It to deliver drilling fluid to the well It is started, the switch 63 is also closed to initiate operation of the motor 28 and activate the remaining parts of the circuit. With the motor 28 in operation, the element 23 is driven away from its normal setting through the driving connection afiorded the gear train 29, 30, the shafts 3| and 24, and the engaged clutch members 32 and 33. Since the motor 28 is a constant speed device, movement of the element 23 away from its normal setting proceeds at a constant rate of speed. As the element 23 is rotated away from its normal setting, it correspondingly rotates the shaft 3 5 through the driving connection afforded by the pulley 45 and the pin 46. In other words, the shaft M and the indicating elements carried thereby follow the movement of the element 23 away from its normal setting. Such rotation of the shaft 44 and the pulley 65 also results in rotation of the torque motor rotor through the connection provided by the string 54.

With the pump H6 in operation, the rocker arm 22 functions intermittently to close the con.- tacts 23. Each time these contacts are closed to indicate a stroke of the pump it, a current pulse is delivered to each of the two stroke counters B4 and 65 in an obvious manner, and also to the operating magnet 53 of the control device 9. When thus energized, the magnet 50 attracts its armature 6! to advance the star wheel 5? one step through the driving connection provided by the shaft 58, the ratchet wheel 59, and the pawl 62. Assumin that the parts of the control device 9 occupy their illustrated positions when any given pulse is delivered to the magnet 60, the.

star wheel 57 is advanced one step to bring a high point 51a beneath the contact spring a, thus moving this spring to first close the contacts 561), then open the contacts 550 and theresuch energization of the motor 52 is without eiiect since the pin 46 is directly engaged with the element Immediately the contacts 56c are opened, the torque motor 52 is deenergized. When thereafter the contacts 55d are closed, a circuit is completed through these contacts and the contacts 551) for energizingthe magnet 33. In operating, this magnet attracts its plunger 42 into engagement with the lower end of the arm M, thereby to move the declutching element 35, the shaft 24 and the clutch member slightly to the right and thus disengage the clutch menuber 33 from the clutch member s2. When thus released from the driving force of the motor 23, the shaft 24 and the parts carried thereby are returned to normal under the influence of the spring 39, which spring is obviously tensioned during movement of the element 23 away from its normal setting. Thus, the element 23 is restored to normal and the shaft 44 is left standing in the position to which it was actuated during movement of the element 23 away from its normal setting.

During the next succeeding pump stroke when the magnet 53 is again energized, the star wheel 5'! is advanced a second step to bring a low point 571) thereof into engagement with the contact spring 56a and thus permit opening of the contacts 56b and 56d and reclosure of the contacts 560. In this regard it will be noted that when the contacts 56b are opened, the magnet 43 is deenergized to permit reengagement of the clutch members -32 and 33 under the influence of the spring 31. It is also noted that the contact springs of the assembly 56 are so arranged that during the described normalizing thereof the con tacts 56b are opened before the contacts 560 are reclosed, thereby to prevent spurious current pulses from being delivered to the motor 52.

Incident to re-engagement of the clutch members 33 and 32, the motor 28 is again rendered operative to drive the element 23 away from its normal setting. The increment of movement which occurs during the interval between pump strokes is, of course, determined by the rate of operation of the pump It. If this rate of operation is decreasing, the interval between the last described pulse delivery to the magnet 60 and the next succeeding pulse will, of course, be of increased length, so that the element 23 will be moved a greater increment away from its normal setting during the pump stroke timing interval under consideration than the increment of movement which occurred during the preceding pump stroke timing interval. In moving beyond its previous off-normal setting, the element 23 further advances the shaft 44 and the indicating elements 513 and did carried thereby away from their respective normal settings, Hence during the next succeeding current pulse interval, in response to which current is again delivered to the torque motor 52 and the release magnet 43 in the order named, the torque motor is still ineffective to rotate the shaft M back toward its normal setting. Energization of the release magnet 43 results in normalizing of the element 23 in the exact manner explained above.

From the preceding explanation, it will be understood that so long as the rate of operation of the pump it decreases to indicate a decrease of the rate of drilling fluid delivery to the well I 8. the increments of movement of the element 23 away from its normal setting which occur during alternate strokes of the pump 15 are progressively increased to progressively move the shaft M and the indicating elements controlled thereby farther away from their respective normal settings. When the pump l6, settles down to a constant rate of operation, representing a constant rate of drilling fluid flow into the well Ill, the increments of movement of the element 23 away from the normal setting of this element become constant. In this case also, the momentary energization of the torque motor 52 which occurs at the end of each pump stroke timing interval is likewise without effect to produce movement of the shaft Ml. Thus, the indicating elements are held in settings representative of the constant rate of drilling fluid. flow into the well It.

When, on the other hand, the rate of operation of the pump 15 increases to indicate that the rate of drilling fluid flow into the well is increasing, the periods separating the current pulses delivered to the magnet I6 become correspondingly shorter. As a result, the increments of movement of the element 23 away from its normal setting which occur during alternate strokes of the pump is are correspondingly decreased, so that in each instance the element 23 stops short of engagement with the pin 29. In such case the momentary energization of the torque motor 52 which occurs at the end of each pump stroke timing interval results in rotation of the shaft 3 a small increment back toward it normal setting by the driving force exerted thereon through the pulley 53, the string 56 and the pulley 55. In this regard it is noted that regardless of the setting of the element 23 relative to the pin 58 at the time the torque motor 52 is energized, this motor is only capable of de veloping sufiicient torque during its momentary energization to 'move the shaft it a small increment back toward its normal setting. Thus, it will be understood that if a large increase in the speed of operation of the pump it occurs and is sustained, several pump cycles will elapse before the torque motor 52 fully returns the shaft 44 to a setting representative of the actual pump speed, i. e. a setting wherein the pin it is engaged with the element 23. The purpose of this arrangement is to prevent the shaft 44 and the c indicating elements carried thereby from following transient increases in the rate of operation of the pump it which may not be truly representative of a sustained increase in the rate of drill ing fluid flow into the Well in.

From the above explanation, it will be apparent that the shaft 44 is controlled rapidly to follow any decrease in the rate of operation of the pump it but only slowly to. follow an increase in the rate of operation of this pump. It will also be understood that the indicating element 50 assumes a setting relative to the scale 5! which is indicative of the rate of pump operation and hence of drilling fluid flow into the Well. Preferably this scale is suitably graduated to indicate the drilling fluid flow directly. Similarly, the wiper arm 37a is variably positioned along the resistor Mb in accordance with the rate of drilling fluid flow into the well Hi. This wiper, when adjustably positioned along the resistor 41?), impresses a variable portion of the voltage of the source 55 across the'termina ls of the indicating instrument 39, this voltage increment increasing with a decrease in the rate of drilling fluid fiow and vice versa. Thus by suitable graduation of the instrument scale, the instrument 49 may be controlled directly to indicate the rate of drilling fluid flow into the well ill.

As indicated above, the counters E i and 65 are provided for directly counting the strokes of the pump 16. Preferably the counter 94 is used to total the number of strokes made by the pump I6 during any given operating period of this pump. The counter 65 is used in conjunction with the counter 64 to indicate when a given increment of drilling fluid entering the Well IE! through the drill pipe I I will return to the surface of the well. To this end, and with the pump 16 in operation, cellophane chips may be introduced into the drilling fluid stream and the number of pump strokes actually required to return the chips to the surface counted by observation of the counter 64. For a given'well depth this information may be used to set the counter 65. Thus, by advancing the setting of the counter 65 ahead of the setting of the counter 6 1 by the number of strokes required on the part of the pump l6 to circulate the chips through the well and then permitting the two counters to continue operating with the indicated difference between the settings thereof, the driller can at any time observe exactly when any given increment of drilling fluid entering the well will return to the surface. This information is important in conventional continuous well logging methods.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein which are within the true spirit and scope of the invention as defined in the appended claim.

What is claimed as new and desired to be se cured by Letters Patent of the United States is:

Apparatus for determining the rate at which a pump delivers fluid to a well during a well drilling operation, comprising constant speed driving means, an element movable by said driving means away from a reference setting to an off-normal setting representative of the rate of fluid delivery into said well, a release magnet, means responsive to energization of said release magnet for returning said element to its reference setting, means responsive to operation of said pump for intermittently energizing said release magnet at a rate which varies in accordance with variations in the rate of operation of said pump, whereby variations in the increments of movement of said element away from said reference setting are produced in response to variations in said pumping rate, an indicating element di rectly actuated by said first-named element to indicate any increase in the increment of movement of said first-named element away from said normal setting, motor means for causing said indicating element to follow any decrease in the increments of movement of said iirst named element away from said reference setting, and means responsive to operation of said pump for energizing and then deenergizing said motor means just prior to energization of said magnet.

JAMES W. PITCHER. JOHN T. CALLAI-IAN, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 7 Number Name Date 1,435,237 Humphrey Nov. 14, 1922 1,476,289 Feder Dec. 4, 1923 2,103,077 Herron n. Dec. 21, 1937 2,290,179 Hayward July 21, 1942 2,385,772 Borden Oct. 2, 1945 FOREIGN PATENTS Number Country Date 375,186 Germany May 8, 1923 

